Raindrops keep falling on my head: When Angel runs out into the street at the end of Surprise, it's raining heavily. Yet at the beginning of Innocence, the rain has abruptly stopped. Many people have regarded this as a continuity error, but we prefer to see it simply as an example of strange Californian weather. There are puddles left on the street, after all.

Smoking is hazardous to your health: Especially the way Angelus takes a drag of the hooker's cigarette. But how come he can suck smoke out of her lungs and blow it out of his own when he doesn't have any breath?

Still, it seems that a cigarette is a vital accessory if you're a bad vamp. By the time Angelus makes it round to Spike and Dru's he's already picked up a packet of tabs somewhere. Of course, when you're dead already, those health warnings kind of lose their impact.

Haven't I heard that somewhere before? "No assembly required," says Buffy of the Judge, referencing an episode title from earlier in the season.

Love 'em and leave 'em: Angelus uses every trick in the book to destroy Buffy, playing on her fears about not measuring up to his expectations, and being seen as 'easy' by him. It makes you wonder just how bad a time Joss Whedon had at high school.

Joss had to put his mouth where his script was in the flashback scenes of Buffy and Angel making love. Too embarrassed to ask the actors themselves to record some heavy breathing for the soundtrack, he and sound editor Cindy Rabideau did the huffing and puffing themselves.

Continuity 101: Despite being fantastic, Innocence suffers from a huge continuity boo-boo. After Angelus' nighttime attack at the school, Xander admits that he may have a plan, and sends Cordelia off to quickly change into "something trashier."

Then Buffy has a dream, wakes up in the morning, goes to school, and attacks Jenny Calendar. Only then do we return to Xander and Cordelia, and it's dark again.

Even Joss Whedon admits the mistake. For the sake of realism, he suggested we "just think of it as them going to Willow's the night before to practice and go over what they were going to do."

Shopping and screaming: The shopping mall scenes were shot inside a Los Angeles department store. Elaborate preparations included constructing a trench to stop the water from the sprinkler system from flooding the shop. The mall's cinema is heavily featured in the episode, and posters for Quest For Camelot, a film being promoted by Warner Brothers at the time, are featured quite prominently.

Willy wacker: In her search for Angel, Buffy "even beat up Willy the Snitch a couple of times." Willy, the seedy barman of Sunnydale's vampire joint, had better get used to it - he comes in for a lot more beatings in later seasons.

Willow works it out: Finally, Willow realises the truth about Xander and Cordelia. Kind of hard not to with them spooning in front of her.

"It's against all laws of God and man!" she shouts, describing herself and Xander as the "We Hate Cordelia club." Of which, she adds, Xander is the treasurer. That would make her the chairman, then.

Sunnydale just keeps getting bigger: So, as well as two schools, an airport and a set of docks, Sunnydale also has its own barracks. For a small California town, it's growing at a grand old rate.

Halloween present: Xander's harrowing Halloween transformation experience seems to have done him some good. He still has all his memories of being a soldier, including "procedure, ordnance, access codes, everything." He's also pretty sure that he "can put together an M-16 in 57 seconds."

No weapon forged: Times have moved on since the Judge last faced any weapons. In his heyday, there was nothing that could defeat him. Nowadays any old bog-standard anti-tank rocket launcher will do the trick.

Sing those tears away: The film Buffy watches with her mother at the end of the episode is Stowaway, a 1936 musical starring Shirley Temple, Alice Faye and Robert Young. The song playing is Goodnight Sweetheart.